Fragrances are of great interest especially in the field of cosmetics and also laundry and cleaning detergents. Fragrances of natural origin are mostly expensive, often limited in their available amount and, on account of fluctuations in environmental conditions, are also subject to variations in their content, purity etc. To circumvent these undesirable factors, it is therefore of great interest, by way of example, to chemically modify readily available natural substances, e.g. readily available fragrances of natural origin, to create substances, which have organoleptic properties that resembles more expensive natural fragrances or which have novel and interesting organoleptic profiles. Such “semi-synthetic” substances can, by way of example, be used as substitutes for purely natural substances on account of their odor, where substitute and natural substance do not necessarily have to have a chemical-structural similarity.
However, since even small changes in chemical structure may bring about massive changes in the sensory properties such as odor and also taste, the targeted search for substances with certain sensory properties such as a certain odor is extremely difficult. The search for new fragrances and flavorings is therefore in most cases difficult and laborious without knowing whether a substance with the desired odor and/or taste will even actually be found.
There is a constant need for novel aroma chemicals with advantageous sensory properties.
Caryophyllene and its analogs are known fragrance chemicals. Caryophyllene is a natural product, which can readily be isolated from clove oil. Some of its main oxidation products are also described in the state of the art.
Skold et al., Food and Chemical Toxicology, 2006, Vol. 44, pp. 538-545, describe the air oxidation of the fragrance chemical beta-caryophyllene to caryophyllene oxide and its allergenic activity.
Collado et al., Nat. Prod. Reports 1998, Vol. 15, pp. 187-204, for example describe the physical properties and reactivity of beta-caryophyllene in detail, including its oxidation products that are obtained from various oxidation reactions.
Matsubara et al., Nippon Nogei Kagaku Kaishi, 1985, Vol. 59, Nr. 1, pp. 19-24, and Uchida et al., Agric. Biol. Chem., 1989, Vol. 53, Issue 11, pp. 3011-3015, describe the oxidation of beta-caryophyllene with lead tetraacetate and the analytical characterization of the obtained oxidation products. Besides 11 other compounds, they identified 1-[(1R,4R,8S)-10,10-dimethyl-7-methylene-4-bicyclo[6.2.0]decanyl]ethanone and 1-[(1R,4S,8S)-10,10-dimethyl-7-methylene-4-bicyclo[6.2.0]decanyl]ethanone in the oxidation product mixture. Specifically, the oxidation reaction is performed by reacting beta-caryophyllene with lead(IV) acetate in stoichiometric quantities, upon which 1-[(1R,4R,8S)-10,10-dimethyl-7-methylene-4-bicyclo[6.2.0]decanyl]ethanone and 1-[(1R,4S,8S)-10,10-dimethyl-7-methylene-4-bicyclo[6.2.0]decanyl]ethanone were obtained in a selectivity of 10.2% and 9.9%, respectively. Furthermore, they propose the potential use of these oxidation products in perfumes, due to their mildly woody odor.